Chapter 13: Solutions and Their Behavior — Flashcards

A set of practice flashcards covering key concepts from Chapter 13: Solutions and Their Behavior, including concentration units, solution processes, solubility, Henry’s law, colligative properties, osmosis, and colloids.

What is molality in solution chemistry?

Molality is the number of moles of solute per kilogram of solvent.

represented by m and uses mol x kg ^-1

^{m= number of moles of solute/ mass of solvent in kilograms}

What is molarity in solution chemistry?

The number of moles of solute per liter of solution.

represented by M and uses mol x L ^-1

^{M = number of moles of solute/volume of solution in liters}

What is mole fraction in a solution?

The ratio of the number of moles of a component (solute) to the total number of moles in all components (solution)

Χn = number of moles of solute / total number of moles of solution.

can solve for either xsolute or xsolvent

xsolute = nsolute/ nsolute+nsolvent

or

xsolvent = nsolvent/nsolute+nsolvent

xsolute + xsolvent = xsolution

What is mass percentage

number of grams of solute in 100g of solution

w/w% = (mass of solute/mass of solution) x 100

What is parts per million?

number of parts of solute in 10⁶  (1 million) parts of a solution is known as parts per million. Used when solute is present in trace amounts.

ppm= (# of parts of one component/ total # of parts of all components) x 10⁶

How do molarity and molality differ in defining concentration?

Molarity uses liters of solution (per L of solution); Molality uses kilograms of solvent (per kg of solvent).

What is solvent in a solution?

The component present in the largest amount; the substance doing the dissolving is the solvent.

What is solute in a solution?

The substance dissolved in the solvent; the minor component.

What is solvation?

The process of dissolving where solvent–solute interactions occur; when the solvent is water, hydration occurs.

What does miscible mean?

Two liquids that mix in all proportions to form a homogeneous solution.

What does immiscible mean?

Liquids that do not mix to form a single solution; they separate into layers.

What is a saturated solution?

A solution that contains the maximum amount of solute that can dissolve at a given temperature.

What is an unsaturated solution?

A solution that can still dissolve more solute at the same temperature.

What is a supersaturated solution?

A solution that contains more solute than is normally possible at that temperature; unstable.

What does 'like dissolves like' mean?

Polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes.

What is hydration?

Solvation by water; the interaction of water molecules with dissolved ions or solutes.

What is Henry’s law?

Gas solubility in a liquid: C(gas) = K(henrys constant) x P(pressure)

solubility of gas is directly proportional to the gas’s partial pressure with K being a constant specific to each gas at given temp 

What is Raoult’s Law?

Psolvent = Xsolvent × P°_solvent; the solvent’s vapor pressure over a solution is reduced by the solvent’s mole fraction.

What are colligative properties?

Properties that depend on the number of solute particles, not their identity.

What is the equation for boiling point elevation?

ΔTbp = Kb × m × i, where i is the van’t Hoff factor.

What is the equation for freezing point depression?

ΔTf = Kf × m × i, where i is the van’t Hoff factor.

What is osmotic pressure?

Π = cRT, where c is the molar concentration (mol/L), R is the gas constant, and T is temperature (K).

What is the van’t Hoff factor (i)?

i - mol particles in solution/mol solute dissolved

ΔT= i K_b M_solute

ΔT= i K_f M_solute

pi = iMRT

i = 1 for nonelectrolytes, greater than 1 for electrolytes (e.g., NaCl → 2, CaCl2 → 3).

How do electrolytes influence colligative properties?

They alter colligative properties in proportion to the number of particles produced (via i).

What is the general definition of a colligative property?

A property that depends on the amount of solute particles, not their chemical identity.

What is osmosis?

Movement of solvent through a semipermeable membrane from higher solvent concentration to lower solvent concentration, toward higher solute concentration.

what is osmotic pressure

1 the pressure required to prevent osmosis across a semipermeable membrane, with isotonic, hypertonic, and hypotonic pressures

What is the Tyndall effect?

Colloids scatter light, giving a cloudy appearance (the Tyndall effect).

What is a colloid?

A system with dispersed particles suspended in a continuous phase, not dissolved, often showing the Tyndall effect.

What is an emulsifying agent or surfactant?

A substance that stabilizes emulsions by lowering interfacial tension; lecithin and soaps are examples.

What is reverse osmosis?

Applying pressure greater than the osmotic pressure to drive water through a semipermeable membrane for purification or desalination.

How are vapor pressures affected in solutions with multiple volatile components (ideal case)?

Vapor pressures add; P_total ≈ P1 + P2 + …, with each Pi = Xi × P°i.

What is the general approach to determine molar mass using colligative properties (boiling point elevation)?

Use ΔTbp = Kb × m × i to find molality, then determine moles of solute from mass of solvent, and calculate molar mass as masssolute / molessolute.

How does solid solubility in liquids typically change with temperature?

For most solids, solubility in liquids increases as temperature increases.

How does gas solubility in liquids generally change with temperature?

Gas solubility decreases as temperature increases.

isotonic pressure

is equal to (=) concentrations

hypertonic solutions

higher (>) concentration of solute outside the cell

hypotonic solutions

lower (<) concentration of solute outside the cell compared to the inside.